Why Cannot L2VPN Map Packets by 802.1p Priority?

Fault Symptom

A port maps packets by 802.1p priority, but L2VPN cannot map packets by 802.1p priority, causing invalid network congestion management.

Involved Products

S6720-EI, S6720S-EI, and S5720-EI

Service Impact

This fault occurs in combined feature deployment scenarios. To obtain information about scenarios where this fault occurs, understand the following basic concepts:

• QinQ termination sub-interface attributes (qinq termination l2 { symmetry | asymmetry })

  • symmetry: specifies that a QinQ termination sub-interface connects to L2VPN in symmetry mode.
  • asymmetry: specifies that a QinQ termination sub-interface connects to L2VPN in asymmetry mode.
  • If this command is not configured, a QinQ termination sub-interface connects to L2VPN in default mode.

• VSI encapsulation mode (encapsulation { ethernet | vlan })

  • ethernet: indicates the Ethernet encapsulation mode.
  • vlan: indicates the VLAN encapsulation mode that meets the 802.1q standard.

• VLL encapsulation mode (mpls l2vc or mpls static-l2vc)

  • raw: indicates the raw encapsulation mode.
  • tagged: indicates the tagged encapsulation mode.

L2VPN fails to map packets by 802.1p priority in the following cases:

• A VSI in VLAN mode is bound to a QinQ sub-interface in asymmetry mode.

• A VSI in Ethernet mode is bound to a QinQ sub-interface or dot1q sub-interface.

• A VLL in tagged mode is bound to a QinQ sub-interface in asymmetry mode.

• A VLL in raw mode is bound to a QinQ sub-interface in symmetry or asymmetry mode.

Solution

To solve this problem, configure ACL-based remarking on the interface. (This solution consumes ACL resources.) The detailed configuration is as follows:

1. Configure ACLs to match 8021p priorities of packets.

   [Switch] acl 4000
   [Switch-acl-L2-4000] rule permit 8021p 0
   [Switch-acl-L2-4000] quit
   [Switch] acl 4001
   [Switch-acl-L2-4001] rule permit 8021p 1
   [Switch-acl-L2-4001] quit
   [Switch] acl 4002
   [Switch-acl-L2-4002] rule permit 8021p 2
   [Switch-acl-L2-4002] quit
   [Switch] acl 4003
   [Switch-acl-L2-4003] rule permit 8021p 3
   [Switch-acl-L2-4003] quit
   [Switch] acl 4004
   [Switch-acl-L2-4004] rule permit 8021p 4
   [Switch-acl-L2-4004] quit
   [Switch] acl 4005
   [Switch-acl-L2-4005] rule permit 8021p 5
   [Switch-acl-L2-4005] quit
   [Switch] acl 4006
   [Switch-acl-L2-4006] rule permit 8021p 6
   [Switch-acl-L2-4006] quit
   [Switch] acl 4007
   [Switch-acl-L2-4007] rule permit 8021p 7
   [Switch-acl-L2-4007] quit
   

2. Configure ACL-based remarking on the main interface of the sub-interface to which a VSI is bound. GigabitEthernet0/0/1 is used as an example.

   [Switch] interface gigabitethernet 0/0/1
   [Switch-GigabitEthernet0/0/1] traffic-remark inbound acl 4000 8021p 0
   [Switch-GigabitEthernet0/0/1] traffic-remark inbound acl 4001 8021p 1
   [Switch-GigabitEthernet0/0/1] traffic-remark inbound acl 4002 8021p 2
   [Switch-GigabitEthernet0/0/1] traffic-remark inbound acl 4003 8021p 3
   [Switch-GigabitEthernet0/0/1] traffic-remark inbound acl 4004 8021p 4
   [Switch-GigabitEthernet0/0/1] traffic-remark inbound acl 4005 8021p 5
   [Switch-GigabitEthernet0/0/1] traffic-remark inbound acl 4006 8021p 6
   [Switch-GigabitEthernet0/0/1] traffic-remark inbound acl 4007 8021p 7
   [Switch-GigabitEthernet0/0/1] quit